In the past various substrates and systems have been proposed to support the growth of plants during the landscaping of surfaces that normally are incapable of supporting plant growth. The need for such landscaping commonly is presented in urban environments in order to improve the appearance of rooftops and other surfaces that otherwise would be devoid of vegetation. Accordingly, the presence of attractive plants is widely recognized to provide needed ornamentation and the desirability of roofscaping is achieving wider and wider acceptance with the passage of time. The presence of plants offers a welcome relief that imparts a natural feeling of well being to what would otherwise be a somewhat barren appearing man-made highly utilitarian environment.
Roofscapes are also known to reduce the undesirable reflection of sunlight from exposed surfaces, to help counteract extremes in temperature and the corresponding impact of such temperature changes upon a roof structure, to impart needed humidity to the atmosphere, and to provide a habitat for plants and small animals in an otherwise barren setting.
It is recognized that roofscapes commonly require periodic care with regular watering as well as other maintenance. It is preferred that such roofscapes be designed so that the care requirements are minimized and the vegetation present therein is as self-sufficient as possible.
Various layers or mats to support plant growth have been proposed for use in roofscapes in the past.
German Patent No. DE 32 33 016 C2 provides for roofscaping based on a vegetation substrate containing lava, sand, and ground clay, plus any other additives if required, such as peat, limestone, and basalt. Vegetation substrates of this type are relatively structurally stable and can be provided in relatively low thicknesses. The latter is of importance in order not to cause excessive static loading of roof areas.
In addition to the positive effects of roofscaping, such landscaping efforts in the past have not addressed the general problem of hazardous substances that are present in the surrounding atmosphere. Alarming concentrations of hazardous substances often are encountered in the ambient atmosphere of urban areas. This is of particular importance in areas in which substantial vehicle exhaust is generated on a dally basis. Despite the requirement that vehicles be equipped with catalytic converters, the atmosphere often is contaminated by hydrocarbons, benzene, NOx, soot, etc. Repeatedly, smog alarms are operative in a number of cities due to excessive quantities of hazardous substances in the atmosphere. Industrial areas, such as those in close proximity to refineries frequently encounter hazardous atmospheric conditions. In spite of air-quality regulations, frequently more could be done to eliminate hazardous materials from the surrounding atmosphere. Furthermore, air filter systems presently in use tend to be elaborate and expensive.
The present invention is based on a basic new concept of expanding the positive effects of roofscapes and linking them with a simple and effective mode for the elimination of hazardous substances from the surrounding atmosphere.
German Patent No. DE 43 09 979 A1 describes a means for cleaning and humidifying air, in particular ambient air, by the roots of specific plants and/or micro-organisms included in the equipment there proposed. This system consists of an electric fan, a plant container open at the top and a suitable filler, with the air to be cleaned and humidified being drawn inside the plant container and passed to the interior of the container. The plant container is arranged within a shell, with the interior of the plant container including an air distributor to disperse the air that is drawn by the fan. Furthermore, the shell consists of an operating unit which can be removed from the shell, in which are arranged a fan, an electronic control for the day/night operation, and a control for water level indication. The interior of the plant container consists of a bottom section containing a coarse-grained porous material extending up to the top edge of the fan distributor, and above that a layer of activated carbon, lava stone, and water-retaining clay pellets to accommodate the root ball of the plant. The function of the filler is not described in detail.
Overall, the prior art techniques for cleaning and humidifying air, in particular ambient air, are designed in such a way that the use of a separate filter can be eliminated, and adequate cleaning and venting will take place without the humidity of discharged air exceeding a specific maximum. While the prior art techniques were mainly used for the cleaning and humidification of air in enclosed areas, they have required a plant container, equipment such as an electronic control, a water level indicator, and an air distributor during use, and such techniques cannot be used for the purpose of the simple elimination of hazardous substances from the surrounding atmosphere in general. For instance, techniques are not feasible from a financial standpoint for dealing with hazardous materials that are present outdoors in the surrounding atmosphere where the quantity of such atmosphere is enormous.